code done + unit tested

Author: Ram swaroop

src/me/ramswaroop/arrays/FixedPoint.java

@@ -0,0 +1,41 @@
+package me.ramswaroop.arrays;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author: ramswaroop
+ * @date: 9/8/15
+ * @time: 11:34 PM
+ */
+public class FixedPoint {
+
+    /**
+     * Finds the FIXED POINT in an array {@param a} of n distinct integers sorted
+     * in ascending order. If there is no fixed point it returns -1.
+     * FIXED POINT in an array is an index i such that arr[i] is equal to i. Note that
+     * integers in array can be negative.
+     *
+     * @param a
+     * @return
+     */
+    public static int findFixedPoint(int[] a) {
+        int low = 0, high = a.length - 1, mid;
+        while (low <= high) {
+            mid = (low + high) / 2;
+            if (a[mid] == mid) {
+                return mid;
+            } else if (a[mid] > mid) {
+                high = mid - 1;
+            } else {
+                low = mid + 1;
+            }
+        }
+        return -1;
+    }
+
+    public static void main(String a[]) {
+        System.out.println(findFixedPoint(new int[]{-10, -5, 0, 3, 7}));
+        System.out.println(findFixedPoint(new int[]{0, 2, 5, 8, 17}));
+        System.out.println(findFixedPoint(new int[]{-10, -5, 3, 4, 7, 9}));
+    }
+}